What makes us unique.Changes in the number and order of genes add variety to the human genome ase pairs Adenine Thymine CID Guanine 9DC098 0 Sugar phosphate backbone U.S.National Library of Medicine Gene-region of the DNA strand that codes for proteins that result in Composite:K.Krause/Science(Human:3D4 medical.com; gene expression. Chromosome:C.Bickel/Science) OS Chromosome-bundle of genes that replicates as a unit 0regonstate Composite: K. Krause/Science (Human: 3D4 medical.com; Chromosome: C. Bickel/Science) What makes us unique. Changes in the number and order of genes add variety to the human genome Gene – region of the DNA strand that codes for proteins that result in gene expression. Chromosome – bundle of genes that replicates as a unit